Circuit Board Mounting Structure and Image Forming Apparatus

This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2024-048172 filed on Mar. 25, 2024, the entire contents of which are incorporated herein by reference.

The present disclosure relates to a circuit board mounting structure for mounting a circuit board on a mounting surface along an up-down direction, and an image forming apparatus.

When a circuit board is fixed to a mounting surface along an up-down direction by a plurality of screws, it is necessary to hold the circuit board so that the circuit board does not fall. That is, in a state in which the circuit board is held in a mounting position along the mounting surface, the plurality of screws are fastened into a plurality of fastening holes formed in the mounting surface.

In addition, it is also known that a hook is provided on the mounting surface, and the plurality of screws are fastened into the plurality of fastening holes in a state in which the circuit board is hooked on the hook.

A circuit board mounting structure according to one aspect of the present disclosure includes a board, a mounting portion, and a plurality of screws. The circuit board has a first side and a second side forming both edges in a first direction, and a third side and a fourth side forming both edges in a second direction crossing the first direction. A mounting portion has a mounting surface formed along an up-down direction, to which the circuit board is attached in a state in which the first side of the circuit board faces upward and the first surface of the circuit board faces the mounting surface. The plurality of screws fasten the circuit board to the mounting portion. The circuit board has a hanging hole and a plurality of screw insertion holes. The hanging hole is formed in a portion of the edge portion along the first side close to the third side, through which a part of the mounting portion is inserted. The plurality of screw insertion holes are holes through which the plurality of screws are inserted. The mounting portion has a hook, a plurality of fastening holes, and a rotation restricting portion. The hook protrudes from the mounting surface and is inserted into the hanging hole to support a supported portion that is an edge portion of the hanging hole on the first side side of the circuit board. The plurality of fastening holes are holes into which the plurality of screws inserted into the plurality of screw insertion holes of the circuit board are fastened. The rotation restricting portion, by coming in contact with the outer edge of the circuit board in a state in which the hook supports the supported portion of the circuit board, restricts rotation of the circuit board around the hook inserted through the hanging hole. The hook has a protruding base portion and a separation restricting portion. The protruding base portion protrudes from the mounting surface and supports the supported portion of the circuit board. The separation restricting portion protrudes upward from the tip-end portion of the protruding base portion and restricts movement of the supported portion supported by the protruding base portion in a direction away from the mounting surface. A dimension of the hanging hole in the first direction of the circuit board is larger than a dimension of the hook in the up-down direction, and a plurality of wire harnesses are wired from the mounting portion side to a second surface of the circuit board via the outer sides of the third side and the fourth side of the circuit board. By bringing the circuit board close to the mounting surface in a state in which the first direction of the circuit board is aligned in the up-down direction, the hook is inserted into the hanging hole and the supported portion is placed on the protruding base portion.

An image forming apparatus according to another aspect of the present disclosure includes a sheet conveying device, a printing device, and the circuit board mounting structure. The sheet conveying device conveys a sheet. The printing device forms an image on the sheet that is conveyed. The circuit board mounting structure is a structure for mounting a circuit board that controls the sheet conveying device or the printing device.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. Note that the following embodiments are examples according to the present disclosure and do not limit the technical scope of the present disclosure.

A circuit board mounting structureaccording to an embodiment constitutes a part of an image forming apparatus.

As shown in, an image forming apparatusincludes a main housing, and a sheet conveying deviceand a printing devicearranged within the main housing.

The sheet conveying deviceconveys a sheet. The sheet conveying deviceincludes a sheet supply mechanismand a plurality of sets of conveying roller pairs. The sheet supply mechanismsends out the sheetsin a sheet storing portionone by one to a sheet conveying path. The plurality of sets of conveying roller pairsrotate to convey the sheetalong the sheet conveying path.

One of the plurality of sets of conveying roller pairsdischarges the sheeton which an image has been formed from the sheet conveying pathonto a discharge tray

The printing deviceforms an image on a sheetconveyed by the sheet conveying device. In the example shown in, the printing deviceforms an image on the sheetby electrophotography.

The electrophotographic printing deviceincludes a laser scanning device, one or more image forming portionsa transfer device, and a fixing device. The image forming portionincludes a photoconductor, a charging device, a developing device, a first cleaning device, and the like.

The charging devicecharges the surface of the rotating photoconductor. The laser scanning devicescans the charged surface of the photoconductorwith a laser beam to form an electrostatic latent image on the surface of the photoconductor.

The developing devicedevelops the electrostatic latent image formed on the surface of the photoconductorinto a toner image. The transfer devicetransfers the toner image from the surface of the photoreceptorto the sheet. The fixing device, by applying pressure and heat to the toner image on the sheet, fixes the toner image to the sheet.

In the example shown in, the printing deviceis a tandem color printing device. In this case, the printing deviceincludes a plurality of image forming portionscorresponding to a plurality of development colors. In addition, the transfer deviceincludes an intermediate transfer belt, and a plurality of primary transfer devicesand secondary transfer devicescorresponding to the plurality of image forming portions

The plurality of primary transfer devicestransfer the toner images from the photoconductorsto the surface of the rotating intermediate transfer beltin the plurality of image forming portionsThe secondary transfer devicetransfers the toner image on the surface of the intermediate transfer beltonto the sheet.

Note that the printing devicemay, for example, be a device that forms an image on the sheetby a method other than the electrophotographic method, such as an inkjet method.

In the image forming apparatus, the circuit board mounting structureis a structure for mounting the circuit boardfor controlling the sheet conveying deviceor the printing deviceto the mounting portion. The circuit boardis a printed circuit board such as a control board or a signal processing board.

For example, a motor that rotates the plurality of conveying roller pairsor a motor drive circuit that drives a motor that rotates the photoconductoris mounted on the circuit board. Alternatively, a signal processing circuit that processes a detection signal from a sensor such as a sheet sensor that detects the sheeton the sheet conveying pathis mounted on the circuit board.

In the present embodiment, the circuit board mounting structureis arranged inside a rear cover of the main housing.

As shown in, in the circuit board mounting structure, the mounting portionhas a mounting surfacealong a vertical direction D. In, the vertical direction Dis the up-down direction.

In the circuit board mounting structure, the circuit boardis fixed to the mounting portionby a plurality of screwswith a first surfaceof the circuit boardaligned along the mounting surface. The circuit boardis mounted on the mounting portionwith the first surfaceand a second surfaceof the circuit boardaligned along the vertical direction D. The first surfaceand the second surfaceare front and back surfaces of the circuit board.

In, a width direction Dis a horizontal direction along the mounting surface. In addition, a depth direction Dis a direction perpendicular to the mounting surface.

When the circuit boardis fixed to the mounting surfacealong the vertical direction Dby a plurality of screws, it is necessary to hold the circuit boardso as not to fall. That is, with the circuit boardheld in the mounting position along the mounting surface, a plurality of screwsare fastened into a plurality of fastening holesformed in the mounting surface.

Incidentally, there are cases where a plurality of electric wiresare wired from the mounting portionside to a front side via the side of the circuit board. In this case, when the circuit boardis mounted, it is necessary to prevent the plurality of electric wiresfrom being pinched between the circuit boardand the mounting portion.

In the circuit board mounting structure, it is desirable to be able to easily mount the circuit boardon the mounting surfacealong the vertical direction Dwhile preventing the plurality of electric wiresfrom being pinched between the circuit boardand the mounting surface.

The circuit board mounting structureincludes a circuit board, a mounting portion, and a plurality of screws. The circuit boardhas a first sideand a second sidethat form both edges of the circuit boardin a first direction D, and a third sideand a fourth sidethat form both edges of the circuit boardin a second direction D(see).

In the present embodiment, the first direction Dis the longitudinal direction of the circuit board, and the second direction Dis the lateral direction of the circuit board(see). The second direction Dcrosses the first direction D. More specifically, the second direction Dis a direction perpendicular to the first direction D.

The circuit boardis attached to the mounting portionwith the first sidefacing upward and the first surfacefacing the mounting surface. The circuit boardhas a hanging holeand a plurality of screw insertion holes(see). The mounting portionhas a hook, a plurality of fastening holes, and a rotation restricting portion(see).

The hanging holeis a hole formed in a portion of an edge portion along the first sideof the circuit board, close to the third sideThe hookof the mounting portionis inserted into the hanging hole. The plurality of screw insertion holesare holes through which the plurality of screwsare inserted.

The hookprotrudes from the mounting surface. The hookis inserted into the hanging holeto support a supported portionof the circuit board(see). The supported portionis an edge portion of the first sideside of the hanging holein the circuit board.

The plurality of fastening holesare holes into which the plurality of screwsinserted into the plurality of screw insertion holesof the circuit boardare fastened. Fastening holesare holes in which screw threads are formed.

The rotation restricting portion, by coming in contact with the outer edge of the circuit boardin a state in which the hooksupports the supported portionof the circuit board, restricts rotation of the circuit boardaround the hookinserted through the hanging hole.

For example, the rotation restricting portioncomes in contact with a portion of the second sideof the circuit boardcloser to the third side(see). Alternatively, it is also conceivable that the rotation restricting portioncomes into contact with a portion of the second sideof the circuit boardcloser to the fourth side

The hookhas a protruding base portionand a separation restricting portion(see). The protruding base portionprotrudes from the mounting surfaceand supports the supported portionof the circuit board(see).

The separation restricting portionprotrudes upward from a tip-end portion of the protruding base portion(see). The separation restricting portionrestricts the movement of the supported portionsupported by the protruding base portionin a direction away from the mounting surface(see). In other words, the separation restricting portionis a retaining portion that restricts the hookfrom coming out of the hanging hole.

An upper edge portion of a portion of the protruding base portionbetween the mounting surfaceand the separation restricting portionis a support portionthat supports the supported portionof the circuit board(see). The support portionis formed along the depth direction D.

The circuit board, by being supported by the hookat the supported portionand restricted by the separation restricting portion, is positioned at the mounting position.

A vertical dimensionH of the hanging holeof the circuit boardis larger than a vertical dimensionH of the hook(see). The vertical dimensionH is the dimension of the hanging holeof the circuit boardin the first direction D. The vertical dimensionH is the dimension of the hookin the vertical direction D.

Similarly, the horizontal dimensionW of the hanging holeof the circuit boardis larger than the horizontal dimensionW of the hook(see). The horizontal dimensionW is the dimension of the hanging holeof the circuit boardin the second direction D. The horizontal dimensionW is the dimension of the hookin the width direction D.

In the circuit board mounting structure, a plurality of wire harnessesare wired. Each of the wire harnessesincludes a plurality of electric wiresand a connectorconnected to one end of the plurality of electric wires(see).

The plurality of wire harnessesare wired from the mounting portionside to the second surfaceof the circuit boardvia the outer sides of the third sideand the fourth sideof the circuit board(see).

A plurality of connectorsare mounted on the second surfaceof the circuit board(see). The connectorsof the plurality of wire harnessesare connected to the plurality of connectors(see).

In the present embodiment, the circuit boardhas a fitting holeformed in a portion of the edge portion along the second sidenear the third side(see). On the other hand, the mounting portionhas a fitting protrusionprotruding from the mounting surface(see). The fitting protrusionfits into the fitting hole.

The circuit boardis supported by the hookat the supported portion, and the fitting protrusionfits into the fitting hole, whereby the circuit boardis positioned at the mounting position with high accuracy.

In the present embodiment, the mounting portionis a sheet metal member. The fitting protrusionis a protrusion formed by half punch processing. Thus, no burrs are formed on the fitting protrusion, and the circuit boardis prevented from being damaged by contact with the fitting protrusion.

The hookis a portion formed by bending a part of a metal plate along the depth direction D. The separation restricting portionof the hookhas a curved contour. Thus, the circuit boardis prevented from being damaged due to contact with the separation restricting portion.

In the present embodiment, the mounting surfaceincludes a plurality of unit mounting surfaces formed at intervals in the vertical direction Dand the width direction D. The mounting surfaceincludes a first mounting surfaceformed near a first end of the mounting portionin the width direction D, and a second mounting surfaceformed near a second end of the mounting portionin the width direction D(see).